Find the piont on the graph of 3x-4y=9 where the y - coordinate is 3 times the x-coordinate

y-coordinate is 3 times the x-coordinate → y = 3x

Substitute to the equation 3x - 4y = 9:

3x - 4 (3x) = 9

3x - 12x = 9

-9x = 9 divide both sides by (-9)

x = - 1

y = 3 (-1)

y = - 3

Answer: (-1, - 3).